Wireless communication is becoming omnipresent in today's society as people increasingly use cordless phones, cellular phones, texting devices, wireless data communication devices, and the like on a daily basis. The need to communicate wirelessly has become pervasive in all types of environments such as residential homes, businesses, retail establishments, roadways, and so forth. To meet this need, however, there are a few problems to overcome in the wireless communication field.
In general, wireless communication relies on the use of a limited resource: the electromagnetic spectrum. Therefore, it is a critical issue how to maximize the use of spectrum without compromising communication quality. Different wireless communication schemes have been introduced to address this issue by utilizing different bands or segments of the electromagnetic spectrum in different manners. Accordingly, many different wireless standards have been created by a government entity, an industry consortium, and/or some other regulatory body to incorporate some of those communication schemes so that each particular segment of the electromagnetic spectrum is utilized in accordance with at least one specific wireless standard. The increasing number of wireless standards drives a need for harmonization.
In addition, when multiple wireless communication devices are employed simultaneously, especially within an overlapping geographic area and frequency spectrum, there is a strong need to minimize the signal interference and improve synchronization. Typically, a wireless communication device operates under a given standard and in accordance with a given communication scheme. In operation, a device generally receives and transmits electromagnetic signal waves that occupy a portion of the total frequency spectrum. Therefore, wireless communication devices are generally designed to operate within a particular frequency band so as to avoid interfering with competing electromagnetic signal waves.
However, when multiple wireless communication devices share the same bandwidth and the same channel with overlapping communication regions, each device must sufficiently identify and distinguish itself from others in order to reduce signal interferences and communicate properly. Also, in the case of a frequency reuse 1 system where the usage of the complete available frequency spectrum is allowed in all cell sectors, the requirement to minimize signal interferences (i.e., achieve a better Signal-to-interference Ratio (SIR)) is very important to the devices in the border areas of the cells, especially at the three-cell contact points. Traditionally, the wireless communication devices are configured to transmit preambles that include individual respective codes that represent respective ones of the wireless communication devices. Unfortunately, these individual codes of the preambles do not adequately differentiate respective transmissions emanating from respective wireless communication devices for a number of reasons.
First, the preambles can be difficult to locate within the electromagnetic spectrum, especially when the subframes containing those preambles are not transmitted regularly under certain standards. For example, compared with the IEEE 802.16 standard, the IEEE 802.16h amendment to the standard contains additional features, such as the listen-before-talk (LBT) feature, which create scenarios where base stations do not transmit frame preambles every time a subscriber station may expect. Second, the preambles as currently specified in some standards, such as IEEE 802.16, may have properties or individual codes that require significant searching and processing by a subscriber station to detect a preamble. Such properties retard preamble detection and hinder network acquisition, especially in a channel-sharing wireless environment. In light of the above, a need exists to improve operations within a co-channel and co-existence wireless communication environment.